Generally, a touch screen is implemented as a touch pad is attached to a display unit. Such touch screen is conventionally mounted to a Personal Digital Assistant (PDA). However, as various types of devices have a Graphical User Interface (GUI) therein, such touch screen is being widely applied to electronic devices such as a navigation system, a Point-Of-Sale (POS) device, an Automatic Teller Machine (ATM), a Portable Multimedia Player (PMP) and a mobile communication terminal.
Generally, a user inputs characters, symbols, or drawings using his or her finger using a touch screen. However, in some cases, an additional electronic pen may be used for precise input.
A method for inputting characters, symbols, etc. using an electronic pen will be explained as follows. Firstly, regions on the touch screen, where desired characters or symbols are positioned, are touched by an electronic pen. The desired characters or symbols are selected from characters or symbols arranged on a keyboard or a keypad displayed on the touch screen. Upon touch of the desired characters or symbols, a change of pressure or electrostatic capacity is sensed on the touch screen. As a result, the desired characters or symbols are displayed on the touch screen.
However, the conventional method for inputting characters or symbols may have the following problems.
Firstly, characters or symbols are densely arranged on the keyboard or the keypad due to a limited size of the touch screen. This may cause a change of pressure or electrostatic capacity not to be precisely sensed on a region on the touch screen, the region with which an electronic pen or a user's finger comes in contact.
As a result, a user's desired characters or symbols are not precisely input. This may lower reliability of the product. Further, it takes a long time to input characters or symbols due to an erroneous operation. This may cause user inconvenience.